
/*
 * Janino - An embedded Java[TM] compiler
 *
 * Copyright (c) 2001-2010 Arno Unkrig. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
 *       following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 *       following disclaimer in the documentation and/or other materials provided with the distribution.
 *    3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
 *       products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.codehaus.commons.compiler.util.resource;

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.zip.ZipFile;

import org.codehaus.commons.compiler.util.iterator.MultiDimensionalIterator;
import org.codehaus.commons.compiler.util.iterator.TransformingIterator;
import org.codehaus.commons.nullanalysis.Nullable;

/**
 * Finds resources in any of the "*.jar" files that exist in a given set of directories.
 */
public
class JarDirectoriesResourceFinder extends LazyMultiResourceFinder {

    /**
     * @param directories The set of directories to search for JAR files.
     */
    public
    JarDirectoriesResourceFinder(final File[] directories) {
        super(new MultiDimensionalIterator<ResourceFinder>(

            // Iterate over directories.
            new TransformingIterator<Object, Iterator<?>>(Arrays.asList(directories).iterator()) {

                @Override protected Iterator<ResourceFinder>
                transform(Object o) {
                    File directory = (File) o;

                    if (!directory.exists()) return Collections.<ResourceFinder>emptyList().iterator();

                    // Iterate over the JAR files in the given directory.
                    File[] jarFiles = directory.listFiles(new FilenameFilter() {

                        @Override public boolean
                        accept(@Nullable File dir, @Nullable String name) {
                            assert dir != null;
                            assert name != null;
                            return name.endsWith(".jar");
                        }
                    });

                    return new TransformingIterator<Object, ResourceFinder>(Arrays.asList(jarFiles).iterator()) {

                        @Override protected ResourceFinder
                        transform(Object o) {
                            File jarFile = (File) o;

                            try {
                                return new ZipFileResourceFinder(new ZipFile(jarFile));
                            } catch (IOException e) {
                                return ResourceFinder.EMPTY_RESOURCE_FINDER;
                            }
                        }
                    };
                }
            },
            2
        ));
    }
}
